A Way to Share Photos, Files And Money in Black & White

Say you want to quickly transfer a file, like a photo or a contact entry, from your smartphone to a friend's. Most people would email or text the file. But a number of technologies have come along to make the process quicker and simpler.

On some Android phones, you can "beam" files like photos from phone to phone by tapping one phone to another, or bringing them very close. But that requires that both phones have a special...